In EP-A198 648 thermoplastic molding compositions are disclosed that contain a spherical hollow filler with a particle size less than 500 μm. The filler has a ratio of external diameter to wall thickness of 2.5-10 and results in an increase in the stiffness and strength at low weight. The scratch resistance or flowability of such molding compositions is not described.
EP-A391413 describes the use of talc as filler in impact-resistance-modified polycarbonate. No influence on the scratch resistance or on the shrinkage due to processing is described.
Highly scratch-resistant molding compositions are known. For example, molding compositions consisting of a thermoplastic material and solid glass beads are disclosed in DE-A2721887. Films made of this material have a good light transmission and scratch resistance. No account is given of the flowability, stiffness or shrinkage due to processing of these molding compositions.
JP-A01-104637 describes mixtures consisting of crystalline polypropylene and modified polypropylene, to which hollow particles consisting of Al2O3—SiO2 have been added. In comparison with a corresponding mixture with talc, an improved scratch resistance with diminished flexural modulus was obtained by virtue of these particles.